RING CORE CURRENT TRANSFORMERS FOR LOW VOLTAGE TYPE AOS F.T.M. S. r. l. Fabbrica trasformatori di misura Via Po, 3 20090 Opera MI - Italy Tel : +39 (0)2 576814 Fax : +39 (0)2 57605296 E-mail: info@ftmsrl.it Website: www.ftmsrl.it MOD.PRG M042-31.05.2007 1 of 7
CONTENTS 1 INTRODUCTION 2 CHOICE OF DEVICES 2.1 SYSTEM SPECIFICATIONS 2.2 ENVIRONMENTAL CONDITIONS 2.3 SAFETY DISTANCES 3 TRASPORT 4 STORAGE 5 INSTALLATION 5.1 CONNECTIONS TO THE MAIN CIRCUITS 5.2 SECONDARY TERMINALS 5.3 CONNECTION TO EARTH'S MAGNETIC CORE 6 COMMISSIONING 7 MAINTENANCE 8 STAFF TRAINING 9 TECHNICAL SPECIFICATIONS MOD.PRG M042-31.05.2007 2 of 7
1. INTRODUCTION This manual provides all the information needed to safely operate measuring current transformer (CT), used in low voltage systems (0.72 kv ) and suitable for installation on cables or bars isolated or immersed in oil and IEC 61869-1 / IEC 61869-2 compliant. 2. CHOICE OF DEVICES Devices must be chosen so as to meet all the electrical parameters of the system in which they will be installed, paying particular attention to the following: 2.1 SYSTEM SPECIFICATIONS Power grid s operating voltage The insulation to the mains voltage, if greater than 0.72 kv, will be guaranteed by the cable or bar through resin or oil and that will serve as primary winding, when inserted into the TA. Rated primary current The primary rated current of the CT is limited by the size of the conductor that passes through it, its value determines the transformation ratio. Rated secondary current All transformer series: 5A or 1A Short circuit thermal current and time All transformer series are guaranteed to bear 100 times the rated primary current for 1 second and limited by the size of the conductor that passes through the CT Short circuit dynamic current All transformer series guarantee 2.5 times the short circuit thermal current and limited by the size of the conductor that passes through the CT Frequency 50 60 Hz Type of use Measure or protection All transformer series comply with the product s standards. Dimensions Weight and dimensions, will be determined according to the characteristics of use MOD.PRG M042-31.05.2007 3 of 7
2.2 ENVIRONMENTAL CONDITIONS Transformers may be subjected to the following environmental conditions, which need to be carefully taken into account: Temperature Insulation class E Altitude All transformer series: up to 1000 m a.s.l. Installation indoor installation or immersed in oil Corrosive agents To be reported if present Dust and deposits To be reported if present 2.3 SAFETY DISTANCES The CT is a component, the safety distances for the installation are defined by the general rules of the apparatus where they are installed. 3. TRASPORT Transformers will be suitably packaged for transport according to the type of product and transport, or to the modality agreed on with the customer. On reception of the device, users are kindly asked to inspect it carefully to ensure the product is undamaged. 4. STORAGE Devices must be stored in clean and dry areas, between -40 C and +70 C (except as otherwise specified). Packaged units may be stacked one on top of another if allowed by and in conformity with the packaging s technical specifications. 5. INSTALLATION All installation operations must be carried out in compliance with all existing accident prevention measures and the following instructions: 5.1 CONNECTIONS TO THE MAIN CIRCUITS The secondary connections must be checked to ensure they are compatible with the wiring diagram and the symbols present on the transformers. The graphics printed on the transformers, showing how to connect them correctly, is as follows, where the primary is the conductor prepared by the user: MOD.PRG M042-31.05.2007 4 of 7
Single primary ratio CT with a secondary winding Primary Single primary ratio CT with two secondary windings Primary Secondary Secondary Double primary ratio CT with the ratio change occurring on the secondary winding and with a secondary winding Primary Secondary The correct connections to obtain the different primary burdens are as follows: example: CT 100-200/5 A-A/A Lowest primary ratio: 100/5 A/A,connect to the secondary terminals: S1 and S2 Highest primary ratio: 200/5 A/A connect to the secondary terminals: S1 and S3 Please pay maximum attention to the conditions of the CTs secondary circuits, which must be connected to the burden or shorted at all times. MOD.PRG M042-31.05.2007 5 of 7
5.2 SECONDARY TERMINALS The secondary terminals are made using copper braid isolated silicon glass, insulation class H. One terminal of each secondary winding must be connected to ground. 5.3 CONNECTION TO EARTH'S MAGNETIC CORE The CT are equipped with a terminal copper braid isolated silicon glass, connected to the magnetic core and isolated at 3 kv for 60 sec, to the secondary winding. 6. COMMISSIONING To guarantee staff and device safety, please make sure, by checking the specifications on the label, that the system s electrical parameters do not exceed the transformer s nominal parameters. The data reported on the identification label are as follows: 1 Series / Type AOS 2 Serial number This is an 8-figure code, in which the first two figures represent the manufacturing year. 3 Insulation reference voltage / Power frequency withstand voltage, expressed in kv 0.72/3 kv (IEC standard-compliant values) 4 Short circuit thermal current and time Expressed in ka and seconds 5 Short circuit dynamic current Expressed in peak ka 6 Frequency Expressed in Hz 7 Product s reference standards. 8 Rated transformation ratio. Rated primary current, A / Rated secondary current, A 9 Burden applied to the secondary terminals to which the accuracy class refers. Expressed in VA 10 Accuracy class 11 Safety factor (if required) 12 Continuous thermal withstand value Percentage referring to rated currents 13 Secondary terminals symbols MOD.PRG M042-31.05.2007 6 of 7
7. MAINTENANCE Before carrying out any operation, make sure that the CTs are not connected to the power grid or powered in any way. Check the tightening of the primary and secondary connections. 8. STAFF TRAINING All installation, commissioning and maintenance operations must be carried out by trained staff. Staff need to be trained in order for them to operate competently within the field. 9 TECHNICAL SPECIFICATIONS For further information on the field of application and technical definitions, please refer to the product s standard: IEC 61869-1 / IEC 61869-2 The products technical datasheets are available online at: www.ftmsrl.it Type AOS 0.72 kv In accordance with the existing law, F.T.M. S.r.l. expressly prohibits any reproduction, retransmission, republication, or other use of all or part of this document without prior authorisation. MOD.PRG M042-31.05.2007 7 of 7